The present invention relates to optical filter driving mechanisms and relates more particularly to an optical filter driving mechanism to drive an optical filter to move in curvilinear direction.
Conventional optical filter driving mechanism is generally operated through belt transmission. Disadvantage of this conventional optical filter driving mechanism is that the driving belt may be caused to deform easily, due to the gravity and the inertia of the filter frame. If the driving belt is deformed during driving operation, the optical filter will vibrate when it is carried to move in front of lens. Further, because the optical filter is driven to make a reciprocating, linear motion, the extended size of the filter frame occupies much space and, a wider space must be prepared for the linear motion of the optical filter. For example, if the optical filter is consisted of 4 pieces of filter at the front of lens 11 of lens-house 1 as shown in FIG. 1, the total track of the filter frame must be wider than the length of filter frame 2 and, a space wider than the total length of 7 pieces of filter must be provided for the reciprocating motion of the optical filter 3.